Ergodic literature is a term coined by Espen J. Aarseth in his book Cybertext—Perspectives on Ergodic Literature, and is derived from the Greek words ergon, meaning "work", and hodos, meaning "path". Aarseth's book contains the most commonly cited definition:

In ergodic literature, nontrivial effort is required to allow the reader to traverse the text. If ergodic literature is to make sense as a concept, there must also be nonergodic literature, where the effort to traverse the text is trivial, with no extranoematic responsibilities placed on the reader except (for example) eye movement and the periodic or arbitrary turning of pages. [1]

Cybertext is a subcategory of ergodic literature that Aarseth defines as "texts that involve calculation in their production of scriptons." [2] The process of reading printed matter, in contrast, involves "trivial" extranoematic effort, that is, merely moving one's eyes along lines of text and turning pages. Thus, hypertext fiction of the simple node and link variety is ergodic literature but not cybertext. A non-trivial effort is required for the reader to traverse the text, as the reader must constantly select which link to follow, but a link, when clicked, will always lead to the same node. A chat bot such as ELIZA is a cybertext because when the reader types in a sentence, the text-machine actually performs calculations on the fly that generate a textual response. The I Ching is likewise cited as an example of cybertext because it contains the rules for its own reading. The reader carries out the calculation but the rules are clearly embedded in the text itself.

It has been argued that these distinctions are not entirely clear and scholars still debate the fine points of the definitions.[3] Under the definition above, Finnegan's Wake, the Critique of Pure Reason, and Being and Time are considered nonergodic literature as they require only "trivial...effort to traverse the text[s]." A stack of stained and mouldering newspapers, on the other hand, is ergodic literature.

One of the major innovations of the concept of ergodic literature is that it is not medium-specific. New media researchers have tended to focus on the medium of the text, stressing that it is for instance paper-based or electronic. Aarseth broke with this basic assumption that the medium was the most important distinction, and argued that the mechanics of texts need not be medium-specific. Ergodic literature is not defined by medium, but by the way in which the text functions. Thus, both paper-based and electronic texts can be ergodic: "The ergodic work of art is one that in a material sense includes the rules for its own use, a work that has certain requirements built in that automatically distinguishes between successful and unsuccessful users." [4]